Swap Magic 3.8 and USB Devices?

Hey I am new here and I was wondering. Can I use an externel HD to boot programs using Swap Magic 3.8? I heard of the various fixes with some backups and I want to use my Seagate to load DVD Loader and such. I have a fat PS2 by the way.

Loading your own programs from USB Mass Storage Devices:
Rename your program to SWAPMAGIC.ELF
Create a folder named SWAPMAGIC in the root directory of your USB Mass Storage Devices and
SWAPMAGIC.ELF file in the folder.
Plug-in the USB Mass Storage Device to the USB port of the PS2, and then boots your PS2 with
program (SWAPMAGIC.ELF) is found in “../SWAPMAGIC/”, it will be launched automatically.

Store multiple programs in the USB Mass Storage Devices:
1. You can put maximum 4 files in the SWAPMAGIC folder at the
same time. You will need to rename those programs to
SMBOOT0.ELF, SMBOOT1.ELF, SMBOOT2.ELF and
SMBOOT3.ELF respectively.
2. Plug-in the USB Mass Storage Device to the USB port of the
PS2, and then boots your PS2 with CODER disc.
3. After booting up your PS2 with CODER disc, you will see a
“BOOT DISC” window
4. Select “SMBOOT” and you will see another window “LAUNCH
SMBOOT”,